JP2009215769A - Underground water fluidization impediment preventing method, construction method of water passing part for preventing underground water flow impediment, and water passing part constructed by the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow impediment preventing method attaining inexpensive and safe construction and hardly affecting environment. <P>SOLUTION: Round steel pipes 9 reaching the depth deeper than a sand layer 4 are embedded in a soil cement column row wall 1 at predetermined spaces in a wall surface direction. The round steel pipes 9 and the soil cement column row wall 1 at a depth part corresponding to the sand layer 4 are formed with a plurality of slits 6 to form the water passing parts 7 allowing underground water to pass through. Underground water upstream of the soil cement column row wall 1 can thereby pass through the water passing parts 7 of the soil cement column row wall 1 and flow downstream. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for preventing the inhibition of groundwater flow in the ground where a retaining wall is constructed.

  When constructing an underground structure by the open-cut method or the like, a water-impervious earth retaining wall is formed in the ground to prevent entry of groundwater into the work area. However, by forming the retaining wall, the flow of groundwater in the ground is obstructed, so that groundwater does not flow downstream of the retaining wall, the water level of the downstream well is lowered, or ground subsidence occurs There was a problem. Therefore, an opening is provided in a portion of the earth retaining wall located in the aquifer to allow the groundwater to flow downstream.

  For example, Patent Document 1 forms a retaining wall composed of a water stop wall up to a predetermined depth deeper than the aquifer and a wall up to a depth shallower than the aquifer, and includes the aquifer. When the ground is frozen to block the flow of groundwater and the underground structure is constructed, a method is disclosed in which the frozen ground is thawed and the groundwater flows downstream.

Further, in Patent Document 2, a vertical working hole is formed at a desired interval on the earth retaining wall made of soil cement at the time of or after the construction, and an impact transmission material such as water is formed in the work hole. A probe for supplying power for plasma generation is inserted, and electric power is supplied to generate a shock wave by plasma to crush the impermeable earth retaining wall, and through the gap generated by this crushing, groundwater A method of flowing water downstream is disclosed.
JP 2000-136528 A JP 2004-124575 A

  However, the method described in Patent Document 1 has a problem in that since a wide range of ground including the aquifer is frozen, it may adversely affect living creatures and plants that inhabit the ground. Furthermore, since a wide range has to be frozen over a long period of time, there is a problem in that capital investment and maintenance costs are incurred and construction costs are high.

  Further, the method described in Patent Document 2 has a problem that the equipment investment cost is high because the apparatus for generating plasma power is expensive. In addition, there is a problem that electric leakage may occur in the vicinity when it rains.

  Then, this invention is made | formed in view of the above conventional problems, It aims at providing the flow inhibition prevention method which has little influence on an environment and can be safely constructed | assembled at low cost. .

  In order to achieve the object, the groundwater flow inhibition preventing method of the present invention is a retaining wall constructed deeper than the aquifer in the ground, and reaches the aquifer or a depth deeper than that. In the method for preventing groundwater flow inhibition in the mountain retaining wall where the pipe reaching the pipe is buried, a crusher capable of injecting high pressure water is inserted into the pipe, and the high pressure water is injected at the position of the aquifer. Thus, an opening step of forming a through hole penetrating to the aquifer is provided. (First invention).

According to the method for preventing the inhibition of groundwater flow according to the present invention, a crusher capable of injecting high-pressure water is inserted into the pipe, and a through-hole penetrating to the aquifer is formed by injecting high-pressure water at the aquifer By doing, groundwater can be made to flow downstream through this through-hole.
And since high pressure water is injected in a pipe | tube, a through-hole can be formed in a mountain retaining wall and a pipe | tube safely.
Furthermore, since the apparatus for producing high-pressure water is a general one, readily available, and inexpensive, the capital investment cost can be reduced.

A second invention is characterized in that, in the first invention, a through-hole penetrating the pipe and the retaining wall is formed in the opening step.
According to the groundwater flow inhibition preventing method according to the present invention, a through hole can be formed in a pipe and a retaining wall.

According to a third invention, in the first invention, the pipe has an opening at the position of the aquifer, and in the opening step, a through-hole penetrating the retaining wall is formed through the opening. It is characterized by that.
According to the groundwater flow inhibition preventing method according to the present invention, a through hole can be formed in a retaining wall.

A fourth invention is characterized in that, in any one of the first to third inventions, the crusher is moved in the pipe by using the inner peripheral surface of the pipe as a guide.
According to the groundwater flow inhibition preventing method according to the present invention, the crusher moves in the pipe in the vertical direction and the circumferential direction with the inner peripheral surface of the pipe as a guide, so that the position, size, etc. of the through hole are accurately formed. can do.

A fifth invention is characterized in that, in any one of the first to fourth inventions, the through-hole is formed in a size that makes it difficult for the earth and sand to flow in accordance with the grain size of the earth and sand in the aquifer.
According to the method for preventing the inhibition of groundwater flow according to the present invention, the through-hole is formed in a size that makes it difficult for the sediment to flow in according to the particle size of the sediment in the aquifer. Does not flow into the hole. Therefore, the through hole is not easily clogged.

According to a sixth invention, in any one of the first to fifth inventions, the through hole is formed in a slit shape.
According to the groundwater flow inhibition preventing method according to the present invention, since the through hole is formed in a slit shape, the pipe is not crushed by earth pressure.

  According to a seventh aspect of the present invention, there is provided a method for constructing a water flow portion, which is a mountain retaining wall constructed deeper than an aquifer in the ground, and a pipe reaching a depth reaching the aquifer or deeper than that. In the construction method of the water flow section for building a water flow section for preventing the flow inhibition of groundwater in the buried retaining wall, a crusher capable of injecting high-pressure water is inserted into the pipe, It is characterized by comprising an opening step of forming a through-hole penetrating to the aquifer by injecting the high-pressure water at the position of the layer.

  The water flow section of the eighth invention is constructed by the construction method of the water flow section of the seventh invention.

  By using the flow inhibition preventing method of the present invention, the influence on the environment is small, and groundwater blocked by a retaining wall can be flowed downstream at a low cost.

  Hereinafter, preferred embodiments of the flow inhibition preventing method of the present invention will be described in detail with reference to the drawings. In addition, although the following embodiment demonstrates the case where the soil cement pillar row wall which is a mountain retaining wall is installed in a natural ground, this invention is applicable also to mountain retaining walls, such as RC, in general.

  1 and 2 are a perspective sectional view and a longitudinal sectional view, respectively, showing a soil cement column wall 1 according to the first embodiment of the present invention.

  As shown in FIGS. 1 and 2, the soil cement column wall 1 penetrates the clay layer 3 of the water-impervious layer and the sand layer 4 of the aquifer layer and reaches the upper part of the Dotan layer 5 of the water-impervious layer. Has been built.

  Round steel pipes 9 that reach a depth deeper than the sand layer 4 are embedded in the soil cement column wall 1 at intervals in the wall surface direction.

  A plurality of slits 6 are formed in a depth portion corresponding to the sand layer 4 of the round steel pipe 9 and the soil cement column wall 1, and the slit 6 serves as a water passage portion 7 through which groundwater can be passed. Therefore, the groundwater on the upstream side of the soil cement column wall 1 passes through the slit 6 formed on the upstream side of the round steel pipe 9 and flows into the round steel pipe 9, and then downstream of the round steel pipe 9. Passing through the slit 6 formed on the side, water can flow to the downstream side of the soil cement column wall 1. The number of installed water passing portions 7 is determined by design and the like, and varies depending on each site.

  In addition, in this embodiment, although the case where this invention is applied to the ground which consists of the clay layer 3, the sand layer 4, and the Dotan layer 5 is demonstrated, it is not limited to this, For example, all the sand layers 4, That is, the ground which consists of an aquifer may be sufficient.

  3-8 is a figure which shows the construction procedure of the water flow part 7 of the soil cement column wall 1 which concerns on 1st embodiment of this invention.

First, as shown in FIG. 3, cement milk is filled in a columnar drilling hole formed by a single-axis or multi-axis earth auger, and a soil cement column wall 1 having soil as an aggregate in the soil is formed. To construct.
The lower end of the soil cement column wall 1 is constructed so as to penetrate the clay layer 3 and the sand layer 4 and reach the upper part of the Dotan layer 5.

  Next, as shown in FIG. 4, a round steel pipe 9 is installed at a predetermined position of the soil cement column wall 1 with a crane 8 installed on the ground. The round steel pipe 9 is built until the lower end of the round steel pipe 9 reaches a depth slightly shallower than the lower end of the soil cement column wall 1. The round steel pipe 9 is built only in the soil cement pillar 1a which is to form the water flow part 7.

  Next, as shown in FIG. 5, the H-shaped steel 10 is built in the soil cement pillar 1b adjacent to the soil cement pillar 1a in which the round steel pipe 9 is built. The H-shaped steel 10 is built until the lower end of the H-shaped steel 10 reaches a slightly shallower depth than the lower end of the soil cement column wall 1.

  Next, as shown in FIG. 6, after the soil cement is hardened, the soil cement in the round steel pipe 9 is crushed and removed by the excavator 11. Since the inner peripheral surface of the round steel pipe 9 is used as a guide for the crusher 22 (described later), the soil cement is not left on the inner peripheral surface of the round steel pipe 9 after the soil cement is removed by the excavator 11. Further, the inside of the round steel pipe 9 is washed to remove as much soil cement as possible.

  Next, as shown in FIG. 7, a crusher 22 capable of injecting high-pressure water is inserted into the round steel pipe 9 from which the soil cement has been removed, and the round steel pipe 9 and the soil cement column array having a depth corresponding to the sand layer 4 are inserted. High-pressure water is sprayed onto the wall 1 to form slits 6 penetrating therethrough.

The crusher 22 has a rod-like nozzle 14 capable of injecting high-pressure water from both ends, a water supply means 18 for supplying high-pressure water to the nozzle 14, and an abrasive supply means 13 for supplying an abrasive to the nozzle 14. I have.
The nozzle 14 has a length slightly shorter than the inner diameter of the round steel pipe 9 and has injection ports at both ends, and simultaneously injects high-pressure water from both ends. Can be formed. The nozzle 14 is detachable from the feed pipe 21 and is attached with a length corresponding to the inner diameter of the round steel pipe 9.
The water supply means 18 includes a water tank 19 for storing water, and a press-fitting pump 20 for pressure-feeding the water in the water tank 19 to the nozzle 14 via the feed pipe 21.
The abrasive material supply means 13 includes an abrasive material tank 16 for storing the abrasive material, and an air compressor 15 for pressure-feeding the abrasive material in the abrasive material tank 16 to the nozzle 14 via the supply pipe 17. It is configured.

Next, a method for forming the slit 6 will be described.
First, as shown in FIG. 7, the nozzle 14 inserted to the vicinity of the lower end depth of the sand layer 4 in the round steel pipe 9 is pulled up to the ground side at a constant speed using the round steel pipe 9 as a guide, Are injected at predetermined time intervals for a predetermined time to form a plurality of slits 6 penetrating the round steel pipe 9 and the soil cement column wall 1a.

In this embodiment, the injection pressure of the high-pressure water is, for example, 2000 kg / cm ² , but is not limited to this value, and the thickness of the round steel pipe 9 and the thickness of the soil cement column wall 1a It is determined as appropriate.

  Next, as shown in FIG. 8, when the nozzle 14 reaches the vicinity of the upper end depth of the sand layer 4, the nozzle 14 is moved to a predetermined angle (for example, in the circumferential direction of the round steel pipe 9 using the round steel pipe 9 as a guide). Rotate by 15 °). Thereafter, while lowering the nozzle 14 toward the bottom of the round steel pipe 9 at a constant speed, a plurality of slits 6 are formed by injecting high-pressure water at a predetermined time interval for a predetermined time as in the case of pulling up. .

  When the nozzle 14 reaches the vicinity of the lower end depth of the sand layer 4, the nozzle 14 is rotated by the above-mentioned angle, and the high-pressure water is jetted again to form the slit 6 while being pulled up to the ground side at a constant speed.

  As described above, the nozzle 14 is moved up and down within the range of the depth portion corresponding to the sand layer 4, and the round steel pipe 9 and the soil cement column wall 1a are rotated by a predetermined angle in the circumferential direction of the round steel pipe 9. The process of forming the slit 6 is repeated until the opening ratio of the slit 6 determined by design or the like is reached based on the flow rate of groundwater acquired in advance by a geological survey or the like.

  Further, the width of the slit 6 is appropriately determined based on the design and the like at the same time when the opening ratio is determined to a size that makes it difficult for the earth and sand to flow in accordance with the particle size of the earth and sand in the sand layer 4. The width of the slit 6 is adjusted by the degree of opening and closing of the nozzle 14.

  By providing a water flow portion 7 composed of a plurality of slits 6 at a depth corresponding to the sand layer 4, the groundwater in the sand layer 4 located upstream of the soil cement column wall 1 is upstream of the round steel pipe 9. It passes through the formed round steel pipe 9 and the slit 6 in the soil cement column wall 1 a and flows into the round steel pipe 9, and then the round steel pipe 9 formed on the downstream side of the round steel pipe 9. It passes through the slit 6 in the inner and soil cement column wall 1a and flows into the sand layer 4 located on the downstream side of the soil cement column wall 1.

  According to the flow inhibition preventing method in the first embodiment of the present invention described above, high-pressure water is injected into the round steel pipe 9 and the soil cement column wall 1a at the depth corresponding to the sand layer 4 to penetrate to the sand layer 4. By forming the slit 6, the groundwater can flow downstream through the slit 6. Moreover, since high pressure water is injected in the round steel pipe 9, the slit 6 can be safely formed in the round steel pipe 9 and the soil cement column wall 1a.

  The width of the slit 6 is opened to a size that makes it difficult for the earth and sand to flow in accordance with the particle size of the sand and sand. Hard to do.

  And since the crusher 22 moves using the inner peripheral surface of the round steel pipe 9 as a guide, the position, length, etc. of the slit 6 can be formed with high accuracy. Furthermore, since the crusher 22 and the water supply means 18 are general, are easily available, and are inexpensive, the capital investment cost can be reduced.

  Next, another embodiment of the present invention will be described. In the following description, portions corresponding to the above-described embodiment are denoted by the same reference numerals, description thereof is omitted, and differences are mainly described.

FIG. 9 is a perspective view showing a soil cement column wall 31 according to the second embodiment of the present invention.
As shown in FIG. 9, round steel pipes 32 having a diameter smaller than that of the round steel pipe 9 used in the first embodiment are embedded in the soil cement column wall 31 at intervals in the wall surface direction.
A plurality of slits 33a and 33b are formed in the depth portions corresponding to the sand layer 4 of the round steel pipe 32 and the soil cement column wall 1, and these slits 33a and 33b allow water to flow through groundwater. 34.

Next, the construction method of the soil cement column wall 31 will be described.
FIGS. 10-13 is a figure which shows the construction procedure of the water flow part 34 of the soil cement pillar row wall 31 which concerns on this embodiment.

  First, as shown in FIG. 10, the round steel pipe 32 is installed at a predetermined position of the soil cement column wall 31 with the crane 8. The round steel pipe 32 has a diameter smaller than that of the round steel pipe 9, and a plurality of slits 33a are provided in advance in a depth portion corresponding to the sand layer 4.

  As with the first embodiment, the round steel pipe 32 is built only on the soil cement column 31a that is to form the water flow portion 34. Also, as shown in FIG. 11, the round steel pipe 32 is built. The H-shaped steel 10 is built in the soil cement column 31b adjacent to the soil cement column 31a. Then, the soil cement in the round steel pipe 32 is crushed and removed by the excavator 11.

Next, as shown in FIG. 12, the nozzle 14 of the crusher 22 is inserted into the round steel pipe 32 from which the soil cement has been removed, and the nozzle 14 is pulled up to the ground side along the slit 33a of the round steel pipe 32. Meanwhile, high-pressure water is sprayed onto the soil cement column wall 31a through the slits 33a to form a plurality of slits 33b penetrating through the portion of the soil cement column wall 31a corresponding to the position where the slits 33a are provided. In the present embodiment, the injection pressure of the high-pressure water is, for example, 500 kg / cm ² , but is not limited to this value, and is appropriately determined depending on the thickness of the soil cement column wall 31a. In addition, since it is only necessary to penetrate the soil cement column wall 31a, it is not necessary to mix the abrasive with the high-pressure water.

  Next, as shown in FIG. 13, when the nozzle 14 reaches the vicinity of the upper end depth of the sand layer 4, the nozzle 14 is rotated by a predetermined angle to the position of the adjacent slit 33a. Thereafter, while descending to the bottom of the round steel pipe 32 along the slit 33a, a plurality of slits 33b are formed by injecting high-pressure water onto the soil cement column wall 31a through the slits 33a in the same manner as when pulling up. Form.

  When the nozzle 14 reaches the vicinity of the lower end depth of the sand layer 4, the nozzle 14 is rotated by the above-mentioned angle, and the high pressure water is jetted again while forming the slit 33 b while pulling up again to the ground side.

  As described above, the nozzle 14 is moved up and down within the range of the depth portion corresponding to the sand layer 4 and rotated by a predetermined angle in the circumferential direction of the round steel pipe 32 so that the high pressure water is supplied to the soil cement column through the slit 33a. The operation of spraying on the row wall 31a to form the slit 33b is repeated.

  According to the flow inhibition preventing method in the second embodiment of the present invention described above, the slit 33b penetrating to the sand layer 4 is formed by injecting high-pressure water onto the soil cement column wall 31a at the depth corresponding to the sand layer 4. By this, groundwater can be made to flow downstream.

  Moreover, since the slit 33a is previously provided in the round steel pipe 32 and the slit 33b is formed only in the soil cement column wall 31a, the discharge pressure of high-pressure water can be made lower than in the first embodiment. Therefore, a small water supply means 18 can be used.

  And since the round steel pipe 32 should just have a diameter which can insert the nozzle 14, a steel pipe with a small diameter can be used. In addition, since the steel pipe having a small diameter is inexpensive, the material cost can be reduced.

  In each of the above-described embodiments, the case where the slits 6, 33a, 33b are formed in the vertical direction has been described. However, the present invention is not limited to this, and as illustrated in FIGS. You may form the slit 41 and the slit 51 of the diagonal direction. The shapes of the slits 6, 33a, 33b, 41, 51 may be round or square, and the shape is not limited.

  In each of the above-described embodiments, the case where the round steel pipes 9 and 32 are used as the pipes embedded in the soil cement column wall 1 has been described. However, the material is not limited to steel, and polyvinyl chloride is used. Alternatively, a tube made of plastic may be used.

  In addition, in each embodiment mentioned above, although the case where round steel pipes 9 and 32 were used as a pipe embedded in soil cement column wall 1 was explained, the shape is not limited to a round shape. A polygonal tube such as a square may be used.

It is a perspective view which shows the soil cement pillar row wall which concerns on 1st embodiment of this invention. It is a longitudinal cross-sectional view which shows the soil cement pillar row wall which concerns on this embodiment. It is a figure which shows the construction procedure of the water flow part of the soil cement pillar row wall which concerns on this embodiment. It is a figure which shows the construction procedure of the water flow part of the soil cement pillar row wall which concerns on this embodiment. It is a figure which shows the construction procedure of the water flow part of the soil cement pillar row wall which concerns on this embodiment. It is a figure which shows the construction procedure of the water flow part of the soil cement pillar row wall which concerns on this embodiment. It is a figure which shows the construction procedure of the water flow part of the soil cement pillar row wall which concerns on this embodiment. It is a figure which shows the construction procedure of the water flow part of the soil cement pillar row wall which concerns on this embodiment. It is a perspective view which shows the soil cement column wall which concerns on 2nd embodiment of this invention. It is a figure which shows the construction procedure of the water flow part of the soil cement pillar row wall which concerns on this embodiment. It is a figure which shows the construction procedure of the water flow part of the soil cement pillar row wall which concerns on this embodiment. It is a figure which shows the construction procedure of the water flow part of the soil cement pillar row wall which concerns on this embodiment. It is a figure which shows the construction procedure of the water flow part of the soil cement pillar row wall which concerns on this embodiment. It is a figure which shows the other shape of a slit. It is a figure which shows the other shape of a slit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Soil cement pillar row wall 1a, 1b Soil cement pillar 3 Clay layer 4 Sand layer 5 Dotan layer 6 Slit 7 Water flow part 8 Crane 9 Round steel pipe 10 H-type steel 11 Excavator 13 Abrasive supply means 14 Nozzle 15 Air compressor 16 Abrasive material tank 17 Feed pipe 18 Water supply means 19 Water tank 20 Press-in pump 21 Feed pipe 22 Crusher 31 Soil cement column wall 31a, 31b Soil cement pillar 32 Round steel pipe 33a, 33b, 41, 51 Slit 34 Water passage

Claims (8)

Preventing the inhibition of groundwater flow in the retaining wall, which is constructed to be deeper than the aquifer in the ground and in which a pipe reaching the depth of the aquifer or a pipe reaching the depth is embedded. In the method
Inserting a crusher capable of injecting high-pressure water into the pipe and injecting the high-pressure water at the position of the aquifer, thereby providing an opening step for forming a through-hole penetrating to the aquifer. A characteristic groundwater flow inhibition prevention method.   The method for preventing flow of groundwater according to claim 1, wherein in the opening step, a through-hole penetrating the pipe and the retaining wall is formed.   2. The groundwater according to claim 1, wherein the pipe has an opening at the position of the aquifer, and in the opening step, a through-hole penetrating the mountain retaining wall is formed through the opening. Flow inhibition prevention method.   The method for preventing the inhibition of groundwater flow according to any one of claims 1 to 3, wherein the crusher is moved in the pipe using the inner peripheral surface of the pipe as a guide.   The method for preventing inhibition of groundwater flow according to any one of claims 1 to 4, wherein the through-hole is formed in a size that makes it difficult for sediment to flow in according to the particle size of the sediment in the aquifer.   The method for preventing flow of groundwater according to any one of claims 1 to 5, wherein the through hole is formed in a slit shape. A mountain retaining wall constructed deeper than the aquifer in the ground, which has a depth reaching the aquifer or a pipe that reaches a depth deeper than that. In the construction method of the water flow part to build the water flow part to prevent,
Inserting a crusher capable of injecting high-pressure water into the pipe and injecting the high-pressure water at the position of the aquifer, thereby providing an opening step for forming a through-hole penetrating to the aquifer. The construction method of the water flow section.   A water flow part constructed by the method for constructing a water flow part according to claim 7.

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